1. Field
The present disclosure generally relates to methods and apparatus for including mode information in a frame for system acquisition, and more particularly to including mode information in a frame preamble concerning whether a transmission in a TDD or FDD mode.
2. Background
In particular communication systems that support both frequency division duplex (FDD) and time division duplex (TDD) communication modes, acquisition of timing information during system acquisition at a user equipment (UE) is dependent on the particular communication mode. Accordingly, a user device operable in such systems has to determine whether a current transmission mode is FDD or TDD before timing acquisition. Various known communication systems, however, do not actively communicate the particular mode of operation, thus leading to difficulty and inefficiency in acquiring timing information during system acquisition.
Further, in particular types of these systems, such as the Mobile Broadband Wireless Access (MBWA) according to IEEE standard 802.20, it is known to employ inserted acquisition information (e.g., AcqInfo) in a preamble of a transmission frame (e.g., a superframe) to assist in system acquisition. This information, however, does not presently communicate whether current transmission to a user device is according to TDD or FDD modes, leading to difficulty in timing acquisition. It is noted, however that the acquisition information (AcqInfo), according to IEEE 802.20, employs a HalfDuplexEnable bit that communicates whether transmissions during FDD mode are full duplex or half duplex, dependent on the binary state of the bit. In TDD modes, however, various different partitions of time divided resources for forward link transmissions (e.g., transmission from a base station or access point (AP) to a user equipment (UE), access terminal (AT) or mobile device) and reverse link transmissions (e.g., transmission from a UE, AT, or mobile device to a base station or AP) is known. If the particular partition ratio of downlink frames to uplink frames is not known by devices in the system, which is typical in known systems, timing acquisition may be further delayed.